From f6e349f0330c3876ede6823c0be6eb2ed9b542ff Mon Sep 17 00:00:00 2001
From: jp9000 <obs.jim@gmail.com>
Date: Wed, 27 Jul 2022 20:20:58 -0700
Subject: [PATCH] libobs/util: Put module load detection in its own func

Puts the detection of obs_module_load in Windows DLLs for the "is this
an obs plugin" check into its own function
---
 libobs/util/platform-windows.c | 136 ++++++++++++++++++---------------
 1 file changed, 74 insertions(+), 62 deletions(-)

diff --git a/libobs/util/platform-windows.c b/libobs/util/platform-windows.c
index c2078e5cb..54a4a1356 100644
--- a/libobs/util/platform-windows.c
+++ b/libobs/util/platform-windows.c
@@ -136,6 +136,79 @@ void os_dlclose(void *module)
 	FreeLibrary(module);
 }
 
+static bool has_obs_export(VOID *base, PIMAGE_NT_HEADERS nt_headers)
+{
+	__try {
+		PIMAGE_DATA_DIRECTORY data_dir;
+		data_dir =
+			&nt_headers->OptionalHeader
+				 .DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT];
+
+		if (data_dir->Size == 0)
+			return false;
+
+		PIMAGE_SECTION_HEADER section, last_section;
+		section = IMAGE_FIRST_SECTION(nt_headers);
+		last_section = section;
+
+		/* find the section that contains the export directory */
+		int i;
+		for (i = 0; i < nt_headers->FileHeader.NumberOfSections; i++) {
+			if (section->VirtualAddress <=
+			    data_dir->VirtualAddress) {
+				last_section = section;
+				section++;
+				continue;
+			} else {
+				break;
+			}
+		}
+
+		/* double check in case we exited early */
+		if (last_section->VirtualAddress > data_dir->VirtualAddress ||
+		    section->VirtualAddress <= data_dir->VirtualAddress)
+			return false;
+
+		section = last_section;
+
+		/* get a pointer to the export directory */
+		PIMAGE_EXPORT_DIRECTORY export;
+		export = (PIMAGE_EXPORT_DIRECTORY)((byte *)base +
+						   data_dir->VirtualAddress -
+						   section->VirtualAddress +
+						   section->PointerToRawData);
+
+		if (export->NumberOfNames == 0)
+			return false;
+
+		/* get a pointer to the export directory names */
+		DWORD *names_ptr;
+		names_ptr = (DWORD *)((byte *)base + export->AddressOfNames -
+				      section->VirtualAddress +
+				      section->PointerToRawData);
+
+		/* iterate through each name and see if its an obs plugin */
+		CHAR *name;
+		size_t j;
+		for (j = 0; j < export->NumberOfNames; j++) {
+
+			name = (CHAR *)base + names_ptr[j] -
+			       section->VirtualAddress +
+			       section->PointerToRawData;
+
+			if (!strcmp(name, "obs_module_load")) {
+				return true;
+			}
+		}
+	} __except (EXCEPTION_EXECUTE_HANDLER) {
+		/* we failed somehow, for compatibility let's assume it
+		 * was a valid plugin and let the loader deal with it */
+		return true;
+	}
+
+	return false;
+}
+
 bool os_is_obs_plugin(const char *path)
 {
 	struct dstr dll_name;
@@ -147,7 +220,6 @@ bool os_is_obs_plugin(const char *path)
 
 	PIMAGE_DOS_HEADER dos_header;
 	PIMAGE_NT_HEADERS nt_headers;
-	PIMAGE_SECTION_HEADER section, last_section;
 
 	bool ret = false;
 
@@ -193,67 +265,7 @@ bool os_is_obs_plugin(const char *path)
 		if (nt_headers->Signature != IMAGE_NT_SIGNATURE)
 			goto cleanup;
 
-		PIMAGE_DATA_DIRECTORY data_dir;
-		data_dir =
-			&nt_headers->OptionalHeader
-				 .DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT];
-
-		if (data_dir->Size == 0)
-			goto cleanup;
-
-		section = IMAGE_FIRST_SECTION(nt_headers);
-		last_section = section;
-
-		/* find the section that contains the export directory */
-		int i;
-		for (i = 0; i < nt_headers->FileHeader.NumberOfSections; i++) {
-			if (section->VirtualAddress <=
-			    data_dir->VirtualAddress) {
-				last_section = section;
-				section++;
-				continue;
-			} else {
-				break;
-			}
-		}
-
-		/* double check in case we exited early */
-		if (last_section->VirtualAddress > data_dir->VirtualAddress ||
-		    section->VirtualAddress <= data_dir->VirtualAddress)
-			goto cleanup;
-
-		section = last_section;
-
-		/* get a pointer to the export directory */
-		PIMAGE_EXPORT_DIRECTORY export;
-		export = (PIMAGE_EXPORT_DIRECTORY)((byte *)base +
-						   data_dir->VirtualAddress -
-						   section->VirtualAddress +
-						   section->PointerToRawData);
-
-		if (export->NumberOfNames == 0)
-			goto cleanup;
-
-		/* get a pointer to the export directory names */
-		DWORD *names_ptr;
-		names_ptr = (DWORD *)((byte *)base + export->AddressOfNames -
-				      section->VirtualAddress +
-				      section->PointerToRawData);
-
-		/* iterate through each name and see if its an obs plugin */
-		CHAR *name;
-		size_t j;
-		for (j = 0; j < export->NumberOfNames; j++) {
-
-			name = (CHAR *)base + names_ptr[j] -
-			       section->VirtualAddress +
-			       section->PointerToRawData;
-
-			if (!strcmp(name, "obs_module_load")) {
-				ret = true;
-				goto cleanup;
-			}
-		}
+		ret = has_obs_export(base, nt_headers);
 
 	} __except (EXCEPTION_EXECUTE_HANDLER) {
 		/* we failed somehow, for compatibility let's assume it